Pyran derivatives and perfume composition containing the same

ABSTRACT

The present invention relates to a novel pyran derivative mixture represented by the following general formula (I): ##STR1## wherein R 1  is H or CH 3 , R 2  is CH 2  or CH 3 , one of the bonds X, Y, or Z is a double bond and the remaining two bonds are single bonds. The present invention relates to a process for the preparation of the above-mentioned pyran derivative mixture. The pyran derivative compound (I) of the present invention is produced by reacting a compound represented by the following formula (II): ##STR2## with a compound represented by the general formula (III): ##STR3## in the presence of an acid catalyst wherein R 1  is as defined above. In addition, the present invention relates to a perfume composition containing an effective aromal amount of the pyran derivative compound represented by the general formula (I) above, in the presence of an acceptable carrier therefore.

TECHNICAL FIELD

The present invention relates to perfumes, and particularly to a pyranderivative mixture, a process for making the pyran derivative mixtureand a perfume composition containing the noval pyran derivative mixture.

BACKGROUND ART

It is known that 2,4-dimethyl-3-cyclohexene-1-carboxyaldehyde,represented by the following formula (II): ##STR4## has a strongleaf-like green aroma (see Perfume and Flavor Chemicals I by SteffenArctander No. 996). However, the compound of the above formula (II) isdisadvantageous because it contains a formyl group making it unstable.

SUMMARY OF THE INVENTION

The present invention relates to a novel pyran derivative mixturerepresented by the following general formula (I): ##STR5## wherein R₁ isH or CH₃, R₂ is CH₂ or CH₃, one of the bonds X, Y, or Z is a double bondand the remaining two bonds are single bonds.

The present invention also relates to a process for the preparation ofthe above-mentioned pyran derivative mixture. The pyran derivativecompound (I) of the present invention is produced by reacting a compoundrepresented by the following formula (II): ##STR6## with a compoundrepresented by the general formula (III): ##STR7## in the presence of anacid catalyst, wherein R₁ is as defined above.

In addition, the present invention relates to a perfume compositioncontaining an effective aromal amount of the pyran derivative compoundrepresented by the general formula (I) above, in the presence of anacceptable carrier therefor. Any conventional and suitable carrier maybe employed in the perfume composition together with the novel fragrantcompounds of the invention.

Accordingly, the present invention provides a novel pyran derivativemixture represented by the general formula (I), a process for thepreparation of the pyran derivative mixture, and a perfume compositioncontaining the pyran derivative mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a H-NMR spectrum of the product obtained in Example 1; and

FIG. 2 is an IR spectrum of the same product.

DETAILED DESCRIPTION OF THE INVENTION

The inventors have accomplished the present invention as a result ofintensive studies to overcome the problem of producing a stable mixturehaving a leaf green aroma. A pyran derivative mixture represented by theabove formula (I) is obtained by reacting compound (II) with a compoundrepresented by the following general formula (III): ##STR8## wherein R₁is as defined above. The resulting pyran derivative is useful as a rawmaterial for the preparation of perfume compositions because thecompound not only has excellent stability, but a persistent and a freshtomato leaf green aroma.

The pyran derivative (I) of the present invention has the followingthree isomers, which can be distinguished by the position of the doublebond: ##STR9## wherein R₁ is as defined above.

The pyran derivative mixture of the present invention can be prepared byreacting, 2,4-dimethyl-3-cyclohexene-1-carboxyaldehyde (II) withcompound (III) in the presence of an acid catalyst. For example, thefollowing reaction formula outlines a method for producing a mixture ofthe three isomers: ##STR10## wherein R₁ is as defined above.

In the above process, although the molar ratio of compound (III) tocompound (II) is not particularly defined, it is preferred to use 0.5 to2.0 mol of the compound (III) per mol of the compound (II). A strongacid is preferably used as an acid catalyst. Examples of acids useful ascatalysts includes sulfuric, p-toluenesulfonic, hydrochloric, andphosphoric acids. The amount of the catalyst, though it depends on thetype of catalyst, is preferably within the range of 0.01 to 10% based onthe amount of the starting material.

The reaction is preferably carried out in a solvent which canazeotropically remove water from the reaction system, since the reactioninvolves dehydration. Hexane, benzene, toluene, xylene, and the like arepreferably used as the solvent.

Since an intermediate (IV) is formed in the process of the presentreaction, as shown in the above reaction formula, the reaction can beeffected either in a one step or in a two step process. The reaction isusually effected at a temperature ranging from 10° to 200° C. If thereaction is effected in one step, the temperature is preferably withinthe range of 50° to 150° C., more preferably from 60° to 120° C. Whenthe reaction is effected in two steps, it is preferred to conduct thefirst reaction at 10° to 100° C. and the second reaction at 50° to 150°C. The reaction time which depends on the reaction temperature, usuallyranges from about 1 to 200 hours.

The product obtained by this process is in a mixture of (Ia), (Ib), and(Ic). The obtained product is preferably used as a mixture, withoutseparation.

As described heretofore, the compound (I) of the present invention isexcellent in stability and has a persistent green perfume aroma liketomato leaf. Accordingly, the present compound can be used for thepreparation of various perfume compositions.

The following examples are given merely as illustrative of the presentinvention and are not to be considered limiting.

EXAMPLE 1

A mixture of 69 g (0.5 mol) of 4-methyl-4-penten-2-ol (72% purity), 69 g(0.5 mol) of 2,4-dimethyl-3-cyclohexene-1-carboaldehyde, and 1 g ofp-toluenesulfonic acid was stirred at room temperature for 96 hours. Themixture was then treated with 100 g of an aqueous sodium carbonatesolution (5%) and washed with water three times. 100 g of xylene and 0.3g of concentrated sulfuric acid were added thereto, and the reaction wascontinued under reflux for 3 hours, the generated water being removedout of the reaction system by azeotropic distillation with xylene. Thereaction product was treated with 100 g of an aqueous sodium carbonatesolution (5%) and washed with water three times. After the solvent andthe low-boiling fractions had been distilled off, the distillation wascontinued to obtain 79 g of a fraction at 110° to 120° C. at 3.5 mmHg.

The obtained fraction was further subjected to precision distillation,yielding 35 g of a fraction at 106° to 108° at 3.5 mmHg. As the resultof the determination of the product by gas chromatography using Carbowax20M (capillary column 50 m) and gas mass spectroscopy, it was recognizedthat the product was a mixture of2,4-dimethyl-6-(2,4-dimethyl-3-cyclohexenyl)-3,6-dihydro-2H-pyran(Ia-CH₃),4,6-dimethyl-2-(2,4-dimethyl-3-cyclohexenyl)-3,6-dihydro-2H-pyran(Ib-CH₃), and2-(2,4-dimethyl-3-cyclohexenyl)-6-methyl-4-methylenetetrahydropyran(Ic-CH₃), which are the compounds of the formulae (Ia) to (Ic), whereinR₁ is CH₃, and the purity of the product was at least 99%. The parentpeak was found at m/e=220. The results of the elementary analysis, ¹H-NMR, and IR are as shown below, from which it was further recognizedthat the obtained product was a mixture of the above-mentioned threecomponents.

Elementary analysis: calculated (%): C 81.76, H 10.98, O 7.26, found(%): C 81.74, H 10.99, O 7.27.

¹ H-NMR, (CDCl₃, TMS as internal reference, δ): FIG. 1

    ______________________________________                                         δ5.4                                                                               ##STR11##                                                                    rings of (Ia-CH.sub.3) and (Ib-CH.sub.3),                                      ##STR12##                                                          4.8                                                                                      ##STR13##                                                         0.9-4.4    complex multiplet (22H)                                            ______________________________________                                    

IR (cm⁻¹): FIG. 2; 2960, 2930, 2900, 1675, 1650, 1440, 1375, 1320, 1220,1170, 1100, 1055, 1025, 890, 860, 820, 805.

EXAMPLE 2

The reaction was effected in the same manner as in Example 1, exceptthat 43 g of 3 methyl-3-buten-1-ol was used in place of4-methyl-4-penten-2-ol. 28 g of a mixture of6-(2,4-dimethyl-3-cyclohexenyl)-4-methyl-3,6-dihydro-2H-pyran (Ia-H),2-(2,4-dimethyl-3-cyclohexenyl)-4-methyl-3,6-dihydro-2H-pyran (Ib-H),and 2-(2,4-dimethyl-3-cyclohexenyl)-4-methylenetetrahydropyran (Ic-H)was obtained. The product was determined by gas chromatography usingCarbowax 20M (capillary column 50 m) and gas mass spectroscopy to revealthat it has a purity of 99% or more. The parent peak was found atm/e=206.

Elementary analysis: calculated (%): C 81.50, H 10.75, O 7.76, found(%): C 81.47, H 10.74, O 7.78.

EXAMPLE 3

A mixture of 238 g (1.7 mol) of2,4-dimethyl-3-cyclohexene-1-carboaldehyde and 238 g (2.0 mol) of4-methyl-4-penten-2-ol having a purity of 72% was added drop by dropunder reflux into a mixture of 180 g of hexane and 3 g of concentratedsulfuric acid over a period of 1 hour. The water generated by thereaction was removed out of the reaction system by azeotropicdistillation with hexane. The reaction was further continued for 8 hoursunder reflux after completing the drop by drop addition of the abovereactants. The reaction product was washed with a 5% sodium carbonatesolution and then with water three times. After the hexane was distilledoff under a reduced pressure, the product was distilled to yield 318 gof a fraction at 100° to 120° C. at 3.5 mmHg. The fraction was subjectedto precision distillation to yield 227 g of a fraction at 106° to 108°C. at 3.5 mmHg (61% yield). The results of the determination of theproduct by gas chromatography, gas mass spectroscopy, elementaryanalysis, ¹ H-NMR, and IR were completely coincident with those ofExample 1.

EXAMPLE 4

Rose oil-type perfume:

    ______________________________________                                        geraniol               250    parts                                           citronellal            200                                                    rosinol                100                                                    phenylethyl alcohol extract                                                                          310                                                    nerol                  30                                                     geranium oil Africa    10                                                                            900                                                    ______________________________________                                    

100 parts of the compound obtained in Example 1 was added to 900 partsof the rose oil having the above composition, whereby a fresh and cleannew rose oil was obtained.

EXAMPLE 5

Bergamot oil-type perfume:

    ______________________________________                                        linalyl acetate       550    parts                                            linalool              300                                                     limonene              30                                                      citral                20                                                      nonyl aldehyde        1                                                       decyl aldehyde        2                                                       a-pinene              5                                                       b-pinene              5                                                       terpineol             20                                                      coumarin              1                                                       petitgrain paraguay   5                                                       ocimene               11                                                                            950                                                     ______________________________________                                    

50 parts of the compound obtained in Example 1 was added to 950 parts ofthe bergamot oil having the above composition, whereby a more natural,sweet and strong-scented bergamot oil was obtained.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention. All suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A compound of the formula (I): ##STR14## whereinR₁ is H or CH₃, R₂ is CH₂ only when Z is a double bond or R₂ is CH₃, oneof the bonds X, Y or Z is a double bond and the remaining two bonds aresingle bonds.
 2. A perfume composition, comprising:an effective aromalamount of the compound represented by the formula (I): ##STR15## whereinR₁ is H or CH₃, R₂ is CH₂ only when Z is a double bond or R₂ is CH₃, oneof the bonds X, Y or Z is a double bond and the remaining two bonds aresingle bonds; and an acceptable carrier therefore.
 3. The perfumecomposition according to claim 2, wherein the perfume further comprisesgeranial, citronellal, rosinol, phenylethyl alcohol extract, nerol andgeranium Africa.
 4. The perfume composition according to claim 2,wherein the perfume further comprises linalylacetate, linalool,limonene, citral, nonyl aldehyde, decyl aldehyde, a-pinene, b-pinene,terpineol, coumarin, petitgrain paraguay and ocimene.